CHADS2 v.1
Risk stratification for stroke based on the CHADS2 score helping to determine the 1 year risk of an ischemic stroke in a non-anticoagulated patient with non-valvular atrial fibrillation. The result is interpreted as 0p - low risk, 1p - 2p - intermediate risk, 3p or more - high risk.
To record an individual's CHADS2 score parameters and total score.
Studies have found that as the CHADS2 score increases, the annual risk of ischemic stroke increases proportionally. Patients with high CHADS2 scores (>2) are at significant risk for stroke: 5.9% annual risk with a score of 3; up to 18.2% annual stroke risk for patients with a score of 6. It is generally recommended that patients with a score >2 be started on warfarin, as the benefits of ischemic stroke prevention outweigh the bleeding risk. According to some studies, patients with a CHADS2 score of 0 may be at low enough stroke risk (0.8-3.2% annual risk) that they can take aspirin (325mg) rather than warfarin as antithrombotic therapy. CHADS2 is an acronym, with each factor contributing points to the total score: - Congestive heart failure 1p - Hypertension 1p - Age ≥75 years 1p - Diabetes1p - Stroke or TSA history 2p The maximum score is 6p and the result is interpreted as; 0p - low risk 1p - 2p - intermediate risk 3p or more - high risk Further interpretation in accordance with [4] 0p - risk of thromboembolic event 1,9% per year 1p - risk of thromboembolic event 2,8% per year 2p - risk of thromboembolic event 4,0% per year 3p - risk of thromboembolic event 5,9% per year 4p - risk of thromboembolic event 8,5% per year 5p - risk of thromboembolic event 12,5% per year 6p - risk of thromboembolic event 18,2% per year
It is recommended to use the CHA2DS2-VASc score over the original CHADS2 score to assess stroke risk in patients with atrial fibrillation. It risk stratifies these patients better than the CHADS2. The CHADS2 score can help physicians estimate stroke risk in patients with non-valvular atrial fibrillation and determine which antithrombotic therapy is most appropriate. Keep in mind: -More recent studies suggest that CHADS2 of 0 points is not necessarily “low-risk” (still 3.2% incidence of stroke per year.) -The more recently developed CHA2DS2-VASc score takes into account other stroke risk factors and may be able to accurately identify which patients are at low enough stroke risk to forgo oral anticoagulation. -Among patients aged 65-95 years old with non-valvular atrial fibrillation, very few (<7%) will be classified as low risk according to the CHADS2 score. -The CHADS2 score does not perform well in the risk stratification of patients with AF who are receiving outpatient elective electric cardioversion. -In one study, 10% of patients with a score of zero were found to have left atrial appendage thrombi on transesophageal echocardiography.
[1] Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA. 2001 Jun 13;285(22):2864-70. [2] Gage BF, van Walraven C, Pearce L, Hart RG, Koudstaal PJ, Boode BS, Petersen P. Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin. Circulation. 2004 Oct 19;110(16):2287-92. Epub 2004 Oct 11.
OBSERVATION.basic_demographic.v1, OBSERVATION.chads2_score.v0, EVALUATION.chads2_assessment.v1
